Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

readOnlyHint=true already covers the safety profile, and the description adds genuinely new behavior: results are ranked by how often they worked, and the playbooks are derived from other agents' experience. It does not mention result limits, whether full steps or summaries are returned, or how ranking interacts with the family parameters beyond what the schema says.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two dense sentences with no filler. Leading with 'How other agents did a task:' front-loads the resource concept rather than a verb, which is slightly less scannable, but the guidance sentence closes the description efficiently.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description needs to convey what comes back, and it does conceptually (distilled steps, pitfalls, ranked by effectiveness). For a read-only single-query search with fully documented parameters, the remaining gaps are minor: nothing about result volume or fallback when no playbook matches.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so every parameter already carries its own explanation including enum values and family-ranking behavior. The description only adds the 'nextjs stripe' style example, a marginal hint about how to phrase query/stack rather than per-parameter meaning, so the baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description concretely defines what a 'playbook' is (distilled steps and pitfalls for a goal from other agents) and covers scope (website or stack like 'nextjs stripe'). It never names the closest sibling, search_runs, so an agent must infer the boundary between searching past runs vs. distilled playbooks.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

'Call this before starting a task' gives a clear, explicit usage trigger rather than leaving timing to inference. It stops short of stating exclusions or pointing at alternatives such as search_runs or get_trajectory when a playbook doesn't exist.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.